The invention relates to devices that fix soft tissue to support structures, particularly devices that fix soft tissue grafts within bone tunnels.
In certain types of surgical procedures, soft tissue grafts must be fixed within a bone tunnel. For example, in anterior cruciate ligament (ACL) replacement surgery, a ligament graft is harvested from the patient or from a donor, and implanted within the knee by securing one end within a bone tunnel drilled through the tibia, and the other end within a bone tunnel drilled through the femur. Several ACL reconstructive techniques are described in Rosenberg, U.S. Pat. No. 5,139,520, which is incorporated herein by reference.
Referring to FIG. 1, a ligament graft 10 can be fixed within a bone tunnel using a bone screw 12. Graft 10 is made from e.g., a single or double long strip of soft tissue. To implant graft 10, the middle of the strip (not shown) is first passed in a distal direction through a first tunnel 14 in the tibia into a second tunnel 18 in the femur, and then attached to the femur tunnel (or attached to bone adjacent the femur tunnel) with a femur fixation device (not shown). Two approximately equal length segments 19a, 19b of the graft extend proximally from the attached middle portion through tunnels 18 and 14. The two ends 20a, 20b of segments 19a, 19b terminate proximal to tibial tunnel 14. Segments 19a and 19b of the graft are then fixed within tibial tunnel 14 by inserting bone screw 12 between the two segments, such that shaft 22 of the screw presses the segments against internal wall 24 of tunnel 14.
In attaching soft tissue within a bone tunnel using a bone screw, it is important that the tissue be rigidly fixed within the tunnel to prevent slippage. When the bone involved is relatively soft (less calcified), a common problem in elderly patients, screws may not adequately fix the graft to the bone.